On Tue, 2 Dec 2014 13:44:06 +0200
"Michael S. Tsirkin" [off-list ref] wrote:

balloon device is not part of virtio 1.0 spec.  Still, it's easy enough
to make it handle endian-ness exactly as other virtio 1.0 devices: what
we gain from this, is that there's no need to special-case it in virtio
core.

Well, the balloon is weird in a number of ways, including its always
little-endian config space.

But I'm not quite sure the spec covers this?

Signed-off-by: Michael S. Tsirkin <redacted>
---
 include/uapi/linux/virtio_balloon.h | 5 +++--
 drivers/virtio/virtio_balloon.c     | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

 struct virtio_balloon_stat {
-	__u16 tag;
-	__u64 val;
+	__virtio16 tag;
+	__virtio64 val;
 } __attribute__((packed));

Would the respective fields in the spec need updating? While it is
actually talking about legacy requirements, the fields are not
specified as __virtio{16,64}.

Also, is changing the stat fields enough? I've not looked into balloon
operation, but does the payload need some endianess conversion as well?